At present, the primary structure of Thin Film Transistor Liquid Crystal Display, (abbreviated to TFT-LCD) comprises an array substrate and a color film substrate (CF) which are box aligned each other, wherein the color film substrate mainly comprises a glass substrate, a black matrix, a color photoresist, and a protection film. In general, the black matrix is arranged in a form of grating, stripe, or dapple between the color pattern formed of the color photoresist. The main function of the black matrix is for blocking scattering light, to avoid the light leak between pixels; the main function of the color photoresist is to produce red-green-blue tricolors by means of color filtering, and then mixing red-green-blue tricolors in different strength ratios to present various colors, such that TFT-LCD displays the full color.
Generally, the main components of a photoresist composition comprise a colorant, an alkali soluble resin, a multi-functional monomer, a photo initiator and so on. In the existing photoresist compositions, a pigment is generally employed as the colorant, and the color mixing is generally performed by adding yellow pigment into the red photoresist and the green photoresist, respectively, and by adding purple pigment into the blue photoresist. However, the contrast of the presently available purple pigment is low, and thereby a purple dye is used for replacing purple pigment in some companies in the art. The photoresist composition is subjected to coating, exposure, and development to form a color photoresist. The dye generally has good solubility in a solvent, therefore in the subsequent development process after the photoresist composition is subjected to exposure, the dye is easily carried away with the developer; in addition, in the further subsequent process of coating the protection film, the dye may enter into the protection film. Therefore, both of the above described two situations may bring about markedly flooding and color shift to the pixel unit.
The defect of the prior art is that, it is easy for the dye in the existing photoresist composition to form flooding, leading to the degradation of the display quality of the display panel.